1. Field of the Invention
This invention relates to an electronic component and to an electronic component module, and in particular relates to an electronic component which is buried so as to be sandwiched between two resin substrates, and to an electronic component module in which the electronic component is buried so as to be sandwiched between two resin substrates.
2. Related Background Art
In order to accommodate the reduction in size and thickness and the higher mounting densities of wiring substrates (package substrates) in recent years, it has been proposed that in addition to IC components, capacitors, resistors, and other chip components be incorporated within substrates. Possible advantages of burying chip components and other electronic components in substrates include increased substrate mounting area, and the ability to manufacture electronic component modules and other electronic circuit substrates with high added value while remaining the same thickness and size. And, by burying capacitors and similar, the wiring length to other active elements can be shortened, so that the occurrence of unwanted electromagnetic radiation can be suppressed, and declines in signal and power transmission velocity can be suppressed, so that high-performance electronic circuit substrates can be manufactured.
For example, in Japanese Patent Application Laid-open No. 2007-242851, a multilayer substrate with incorporated components is disclosed which is a multilayer substrate with incorporated components in which a stacked member, in which multiple layers of circuit substrates having circuits formed on substrate insulating material are stacked, incorporates at least one type of active components such as semiconductor ICs; by making the substrate insulating material, on which circuits are formed connecting the components, a polyimide film the average linear expansion coefficient (CTE) in the range 100° C. to 350° C. of which is in the range −5 (ppm/° C.) to +20 (ppm/° C.), warping due to stacking of different materials, and separation of components and circuits, are prevented.
However, electronic components buried in a substrate as described above must be of low height, or formed on extremely thin foil, in order to enable burial in the substrate. For this reason the areas of the side-face adhesion portions of capacitors and other electronic components are small, and there is the problem of adhesion of the side faces of electronic components with the substrate. Further, when burying electronic components in resin or similar, a gap may be formed between a side face of an electronic component and the resin. When for example solder reflow or similar is used to mount ICs on the substrate, because the substrate is subjected to thermal cycles, so that the substrate expands and contracts, and so abnormal stresses may be concentrated at such gaps, giving rise to problems of strength and reliability.